Arvo Pärt's reputation as the leading "holy minimalist" is founded upon his vocal music. The compositional approach that he developed in the 1970s, with its chaste interleaving of contrapuntal lines and gently hocketing entries, lends itself superbly to writing for voices. It was the series of works he produced in that style - often called tintinnabulation - from the 1982 St John Passion onwards, that established Pärt as a highly distinctive figure in European music.

In most of his later compositions, instruments, if they are present at all, have tended to take a subsidiary role to the voices; Pärt has not been tempted, it seems, to repeat the success of his remarkable double violin concerto from 1977, Tabula Rasa. But in the three recent works on the latest of ECM's continuing series devoted to his output, an orchestra does feature more or less prominently, and Orient and Occident, composed two years ago, has no vocal contribution whatsoever. That is still, though, based upon a text, and grounded in a melodic line, gently suffused with an oriental flavour, that runs through the entire seven-minute piece. The effect, as in so much of Pärt's music, is one of profound introspection, a string meditation that is as economical with its emotions as it is with its material.

Pilgrim's Song is an arrangement made last year for men's choir and string orchestra of a piece originally composed in 1984, as a memorial to an Estonian film-director friend of the composer. Psalm 121 ("I will lift up mine eyes unto the hills") is intoned by the choir on a single pitch between paragraphs of gently lapping string lines to create a simple, monumental effect.

In the 1998 Como Cierva Sedienta, however, the relationship between the chorus and the orchestra is more involved and the effect much weightier. Pärt uses wind as well as strings, and separates the settings of the texts with instrumental ritornelli and interludes, which sometimes have a neoclassical feeling, not that far removed from Stravinsky.

Unusually for ECM there is little documentation, except for the texts for Pilgrim's Song and Como Cierva Sedienta. The notes about the music itself, by the composer and his wife, are very brief, presumably to allow the works to speak for themselves, which they do in Pärt's eloquent, understated way.